how to do Background Subtraction in opencv (opencv-master) python

Question

I am using Enthought Canopy as my IDE(python with opencv-masters), i want to do Background Subtraction, but the problem is, the webcam(window which starts with webcam) is not responding if I run the code. My code is:

import cv2
import numpy as np
cam=cv2.VideoCapture(0)
fgbg = cv2.BackgroundSubtractorMOG()
while(cam.isOpened): 
   f,img=cam.read()
if f==True:
     #img=cv2.flip(img,1)
     #img=cv2.medianBlur(img,3)
     fgmask = fgbg.apply(img)
     cv2.imshow('track',fgmask)
if(cv2.waitKey(27)!=-1):
   cam.release()
   cv2.destroyAllWindows()
   #break 

I have no idea whether I can achieve this Background Subtraction in any other ways.

Thanks!

Answer 1

if f==True and if(cv2.waitKey(27)!=-1) should be inside the while loop, then it works fine

import cv2
import numpy as np
cam=cv2.VideoCapture(0)
fgbg = cv2.BackgroundSubtractorMOG()
while(cam.isOpened): 
   f,img=cam.read()
   if f==True:
       #img=cv2.flip(img,1)
       #img=cv2.medianBlur(img,3)
       fgmask = fgbg.apply(img)
       cv2.imshow('track',fgmask)
   if(cv2.waitKey(27)!=-1):
       cam.release()
       cv2.destroyAllWindows()
       #break